In particular in the area of dental treatments, many systems for optical acquisition of the three-dimensional geometry of objects are known. The latter are used, for example, in the creation of prostheses, crowns, fillings, or the like, are used to support the monitoring of orthodontic treatments, and/or are used to assist quite generally in the observation or acquisition of intraoral structures. The great advantage of such optical systems lies, on the one hand, in that they are neither invasive nor unpleasant as is the case of, for example, the dental impression frequently used in conventional dentistry and in that they also do not pose any potential danger to the patient, as is the case, for example, in radiation-based methods, such as X-rays. On the other hand, after the acquisition, the data are present in electronic form and can be easily stored, for example for later comparisons, or else can be forwarded, for example, from a dentist to a dentistry laboratory.
One problem that always arises in the optical method for acquisition of the three-dimensional geometry of objects, in particular teeth, is that soft parts that are present in the oral space, such as the insides of the cheeks or the tongue, are unintentionally acquired. It is usually difficult to correct such erroneous images after the fact, since even in the systems that provide several images of the same area, the erroneous images affect the geometry that is acquired or calculated and falsify the latter. Systems that join many individual areas to one another (“stitching”) can overcome such erroneous measurements even less well since frequently no link can be found between individual areas. The object of the invention is therefore to make available a method that lessens this problem.